Vertical lift machine

ABSTRACT

A maneuverable lifting body wherein pressurized gas is discharged at supersonic velocity over the surface of a downwardly sloping surface, the supersonically flowing gas separating and thereafter reattaching to the surface to provide a low-pressure region intermediate the points of separation and reattachment. The low-pressure region created on the upper surface, in cooperation with atmospheric pressure on the bottom of the body, results in vertical lifting forces which add to the vertical component of the momentum forces of the gas.

United States Patent [72] Inventor Raymond V. Thompson 3,045,948 7/1962 Howie 244/12 Slmsbury. Conn. 3,276,723 10/1966 Miller et al. 244/12 [211 App]. No. 836,393 3,297,278 1/1967 Hawkins 244/23 [22] Filed June 25,1969 3,463,418 8/1969 Miksch 4 244/41 [45] Patented July I3, I971 3,469,802 9/l969 Roberts et al 244/12 [73] Assignee svhl fi llg s Primary Examiner-Milton Buchler est o Assistant Examiner-Steven W. Weinrieb Attorney- Fishman and Van Kirk [54] VERTICAL LIFT MACHINE 1o Chm 3 Driving as. AB STRAT maneuverable lifting body wherein pressunzed gas IS discharged at supersonic velocity over the sur- [52] US. Cl. 2445/12 f f a downwardly sloping fa the supersonicany fl [51 i B649 29/00 ing gas separating and thereafter reattaching to the surface to [50] Field of Search 244/12, 23 provide a 1ow preSSm-e region intermediate the points f separation and reattachment. The low-pressure region created [56] kahuna cued on the upper surface, in cooperation with atmospheric pres- UNITED STATES PATENTS sure on the bottom of the body, results in vertical lifting forces 2,468,787 5/1949 Sharpe 244/12 C which add to the vertical component of the momentum forces 2.801.058 7/1957 Lent 244/12 ofthe gas.

I4 I 1 l I I I6 1/ p IO 26 PATENTED JUL] 3:911 3,592,413

FIG. 2 .4

l I l I I6 INVENTOR i & RAYMOND v THOMPSON F/SHMA/V 8 VAN KIRK ATTORNEYS VERTICAL LIFT MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the creation of lifting forces. More specifically, the present invention is directed to vertical lift machines involving boundary layer separationreattachment control. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.

2. Description of the Prior Art While not limited thereto in its utility, the present invention is particularly well suited for application to self-lifting bodies, such bodies sometimes being referred to as hovercraft. It is to be noted that the hovercraft must be distinguished from the ground effect machine (GEM) or air cushion vehicle which creates and rides upon an air cushion established by drawing in atmospheric air and directing it downwardly beneath the vehicle. The hovercraft, the most common example of which may be considered to be the helicopter, is not constrained to operation within a few feet ofa surface as is the GEM but rather creates its own lift in somewhat the same manner as a conventional aircraft.

Prior art operational hvercraft have been characterized by a rotating airfoil or propeller which has generated the necessary lifting forces in a conventional manner. The complexities of such rotating blade mechanisms, particularly in the helicopter environment where blade pitch must be constantly changing, are well known and will not be discussed herein. In addition to those vehicles which employ a rotating, generally horizontally mounted propeller mechanism, a number of selflifting bodies have been proposed wherein air would be discharged outwardly in all directions from a region approximating the center of the vehicle over an immobile airfoil structure so as to generate vertical lift. In the latter type apparatus it was generally proposed to blow air over both upper and lower airfoil surfaces, lift being provided in the conventional aerodynamic manner.

The previously proposed lifting bodies of the immobile airfoil-type have not been the subject of development due to the obvious inefficiencies in their design. That is, if reduced to practice, prior art designs would inherently provide exceedingly limited lift and thus little or no load-carrying capacity. Perhaps more importantly, no practical manner of maneuvering such vehicles has been proposed. The lack of maneuverability, with the exception of relatively expensive helicopter-type vehicles, has also characterized the rotating propeller-type lifting bodies. Lack of maneuverability is, of course, a serious disadvantage in cases where the device is to be used as an observation platform during military activities. Previous attempts at using comparatively inexpensive, camera-bearing lifting bodies in the field have met with failure since the devices could only be positioned vertically above and connected to the launch site and would thereby reveal the position of the crew.

SUMMARY OF THE INVENTION The present invention overcomes the above-discussed and other disadvantages of the prior art and, in so doing, provides a novel and improved vertical lift machine. In accomplishing the foregoing, the present invention generates vertical lift by creating a pressure differential across an outwardly flaring plate or skirt. Subatmospheric pressure is created at the top of the skirt, which would typically be of conical shape, through the use of supersonic flow discharging from an annular, convergent-divergent nozzle. The supersonic flow separates and thereafter reattaches to the conical plate to provide a lowpressure region on the upper surface of the plate intermediate the points of separation and reattachment. Atmospheric pressure acts on the underside of the lifting body thereby providing the requisite pressure differential. The vertical lifting forces resulting from this pressure differential and the vertical component of the momentum forces of the supersonic gas stream combine to provide the vertical lift.

The present invention is further characterized by an upper cap assembly into which pressurized fluid is discharged by the propulsion source, the propulsion source typically comprising a gas turbine engine mounted vertically with its discharge nozzle facing into the cap. The cap may be mounted from the conical plate by means which permit tilting of the cap. In the preferred embodiment the cap and plate cooperate to define the nozzle which creates the supersonic flow. Maneuverability of the vehicle may be achieved by tilting the cap so as to choke the flow at one side of the body. Alternatively, maneuverability may be achieved by release of some of the gas from the cap into a stagnation chamber, the chamber having a horizontally oriented and steerable discharge nozzle.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to FIG. I, a perspective view of a first embodiment of the present invention may be seen. The embodiment of FIG. 1 is possessed of a generally conical shape and the upper surface of the load-carrying portion of the vehicle is defined by a conical metal plate indicated generally at 10. The vehicle body defined in part by plate 10 has an opening at its upper or smaller diameter end. Air under pressure is discharged vertically upwards about the axis of the vehicle through this opening.

Mounted from the vehicle and above the smaller diameter end of plate 10 is a cap assembly indicated generally at 12. Cap assembly 12 is, as may best be seen from FIG. 3, hollow and has a riser portion 14 into which the pressurized fluid from the propulsion source is discharged. The cap assembly 12 also has, about the lower periphery of riser portion 14, an outwardly extending flange 16. The bottom surface of. flange -16 and the upper or smaller diameter end of the conical plate 10 cooperate to define an annular convergent-divergent nozzle 18 through which pressurized gases discharged into cap 12 will escape. Fluid flowing through nozzle 18 will, as a result of the pressure within cap 14 and the nozzle design, be discharged down over the exterior of plate 10 at supersonic velocity.

As may be seen from a consideration of the embodiment of FIG. 2, the vehicle may be provided with a load space 20 which is defined in part by the inner surface of conical plate 10 and by a baseplate 22. In a typical operational configuration, where the lifting body of the present invention would be employed as a remotely controlled and unmanned observation platform, electronics including maneuvering control servosystems, controllable television cameras and transreceivers would be mounted in load space 20. Additional load space may be provided on top ofcap l2 and cameras may be located in or on such additional space.

Also mounted within the lifting body and coaxial with conical plate 10 will, as can also be seen from FIG. 2, be a propulsion source 24. In the preferred embodiment, propulsion source 24 will comprise a gas turbine engine installed vertically with its discharge nozzle 26 facing the interior of cap assembly 12. The combustion products discharged under pressure to nozzle 26 will be directed into cap 12 and will flow outwardly from the cap through the nozzle 18 as shown diagrammatically in FIG. 3.

In the embodiment of FIG. l, in the interest of maneuverability, the cap 12 is provided with a rotatable upper section 30. Cap section 30 defines, in its interior, a stagnation chamber which may be placed into communication with the interior of the lower cap section via suitable valving. The stagnation chamber has a discharge nozzle 34 which may be aimed by rotating cap section 30 by means not shown. Accordingly, horizontal maneuvering thrust may be generated by placing the stagnation chamber into communication with the interior of the lower cap section whereby engine exhaust gas will be discharged through nozzle 34 and the cap rotated so as to point the nozzle 34 in the desired direction.

Alternately, or in addition to the employment of a rotatable cap section and associated structure as above described, the maneuvering control of FIG. 2 may be utilized. In the FIG. 2 scheme the cap 12 is mounted from plate 10 by a plurality of linkage mechanisms, such as the double-pivot linkage 36. Accordingly, the cap 12 may be tilted to any desired angle relative to a vertical axis through the vehicle to thereby unbalance the horizontal momentum component of the gases exhausting through nozzle 18. The means for moving linkages 36 have been omitted from the drawing in the interest of clarity.

Operation of the present invention may be best understood by consideration of FIG. 3 which shows a cross section of the discharge nozzle 18. In FIG. 3, P, represents the supply pressure in cap assembly 12 of a gas being admitted to threedimensional convergent-divergent nozzle 18. The dimensions of the upper end of the conical plate 10 and the lower surface of flange 16, the plate and flange cooperating to define nozzle 18, are chosen so that asymmetric separation of the supersonic gas jet discharging from nozzle 18 from plate I will occur along line A-A at the downstream end of the nozzle. The effect of the flat annular plate attached to the convergent-divergent nozzle 18 is to promote a process of turbulent mixing between the separating jet boundary and the ambient gas trapped adjacent to the plate thereby resulting in a lowpressure region. Restated, gas discharged from nozzle 13 flows at supersonic velocity over the surface of plate 10 and, in the manner known in the art, separates from the plate at point A and thereafter reattaches to the plate at point B a substantial distance downstream from point A. Ambient gas trapped between the points of separation and reattachment will be mixed with and entrained in the supersonic stream thereby creating a near vacuum on the surface of the plate between points A and B. Obviously, the combined effect of the lowpressure region acting on the upper surface of plate 10 and atmospheric pressure acting on the bottom of the vehicle (plate 22) will create a lifting force. This lifting force, when combined with the vertical component of the momentum of the gases being discharged from nozzle 18, will create sufficient lift whereby the vehicle will rise vertically.

Referring again to FIG. 2 it is to be noted that conical plate 10 may be provided with a vertically movable, outboard section 40. Downward movement of annular section 40 out ofthe usual plane of plate 10 will increase the length of the vortex between points A and B by moving the reattachment point of the supersonic gas stream downstream. Increasing vortex length will enhance lift by enlarging the area of the near vacuum region created above the surface of plate 10.

Considering again FIG. 3, tests have shown that angle 0 defined by the divergent portion of nozzle 18 should be in the range of 3050. This design parameter can, however, be satisfied by making angle a as great as 90. When angle a is 90, flange l6 obviously flares outwardly and upwardly and there will be no vertical momentum component to be added to the lift generated by the created pressure differential.

While a preferred embodiment has been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the present invention. Accordingly, it is to be understood that the present invention has been described by way ofillustration and not limitation.

What I claim is:

1. Apparatus for the generation of vertical aerod namic forces corn rising:

ah ting body, said bo y having a discharge port in its upper surface-defining portion;

chamber-defining means mounted on said body and above said discharge port, said chamber-defining means cooperating with said upper surface-defining portion of said lifting body to define an annular convergent-divergent nozzle; and

means positioned within said lifting body and discharging pressurized fluid through said discharge port and into said chamber-defining means, said fluid in turn being discharged from said nozzle over said upper surfacedefining portion ofsaid body at supersonic velocity.

2. The apparatus of claim 1 wherein said lifting body comprises:

an annular plate, said plate defining the upper surface of said body; and

a base member connected to said plate, a load space being defined on the interior of said body between said plate and member.

3. The apparatus of claim 1 wherein the divergent portion of said nozzle defines an angle of from 30'to 50.

4. The apparatus of claim 3 wherein said lifting body comprises:

an annular plate, said plate defining the upper surface of said body; and

a base member connected to said plate, a load space being defined on the interior of said body between said plate and member.

5. The apparatus of claim 4 wherein said fluid-discharging means comprises;

a gas generator.

6. The apparatus of claim 5 wherein said gas generator comprises:

a gas turbine engine mounted vertically within said body.

7. The apparatus of claim 6 wherein said base member comprises:

a second annular plate, said second annular plate defining an inlet nozzle for said engine.

8. The apparatus of claim 7 wherein said annular upper surface-defining plate is frustoconical in shape and is coupled to said second annular plate about its periphery.

9. The apparatus of claim 4 further comprising:

means for unbalancing the horizontal thrust component of the gases discharged through said nozzle whereby horizontal maneuvering of said body is permitted.

10. The apparatus of claim 4 wherein said annular plate comprises:

a first frustoconical member, said first member defining said discharge port and cooperating with said chamber defining means to define said nozzle;

a second frustoconical member positioned outwardly from said first frustoconical member; and

means for vertically moving said second frustoconical member relative to said second frustoconical member.

lifting 

1. Apparatus for the generation of vertical lifting aerodynamic forces comprising: a lifting body, said body having a discharge port in its upper surface-defining portion; chamber-defining means mounted on said body and above said discharge port, said chamber-defining means cooperating with said upper surface-defining portion of said lifting body to define an annular convergent-divergent nozzle; and means positioned within said lifting body and discharging pressurized fluid through said discharge port and into said chamber-defining means, said fluid in turn being discharged from said nozzle over said upper surface-defining portion of said body at supersonic velocity.
 2. The apparatus of claim 1 wherein said lifting body comprises: an annular plate, said plate defining the upper surface of said body; and a base member connected to said plate, a load space being defined on the interior of said body between said plate and member.
 3. The apparatus of claim 1 wherein the divergent portion of said nozzle defines an angle of from 30* to 50*.
 4. The apparatus of claim 3 wherein said lifting body comprises: an annular plate, said plate defining the upper surface of said body; and a base member connected to said plate, a load space being defined on the interior of said body between said plate and member.
 5. The apparatus of claim 4 wherein said fluid-discharging means comprises; a gas generator.
 6. The apparatus of claim 5 wherein said gas generator comprises: a gas turbine engine mounted vertically within said body.
 7. The apparatus of claim 6 wherein said base member comprises: a second annular plate, said second annular plate defining an inlet nozzle for said engine.
 8. The apparatus of claim 7 wherein said annular upper surface-defining plate is frustoconical in shape and is coupled to said second annular plate about its periphery.
 9. The apparatus of claim 4 further comprising: means for unbalancing the horizontal thrust component of the gases discharged through said nozzle whereby horizontal maneuvering of said body is permitted.
 10. The apparatus of claim 4 wherein said annular plate comprises: a first frustoconical member, said first member defining said discharge port and cooperating with said chamber defining means to define said nozzle; a second frustoconical member positioned outwardly from said first frustoconical member; and Means for vertically moving said second frustoconical member relative to said second frustoconical member. 